1. Field of the Invention
The present invention relates to a semiconductor light emitting device and a method of manufacturing the same, and more particularly, to a nitride semiconductor light emitting device and a method of manufacturing the same, which can achieve high resistance to electrostatic discharge (ESD), and high light extraction efficiency.
2. Description of the Related Art
Light emitting diodes (LEDs), as one type of semiconductor light emitting device, generate light of various colors by electron-hole recombination occurring at a p-n junction when current is applied. LEDs are greatly advantageous over filament-based light emitting devices. That is, LEDs have a longer useful life span, lower voltage, superior initial driving characteristics, high vibration resistance and a high tolerance to repetitive power connection/disconnection. This has led to a continually increasing demand for LEDs. Notably, of late, a great deal of attention has been drawn to group III nitride semiconductors capable of emitting light in the short wavelength region including a blue-light region.
In general, group III nitride semiconductors (hereinafter, referred to as ‘nitride semiconductors’) have a composition of AlxGayIn1-x-yN where 0≦x≦1, 0≦y≦1 and 0≦x+y≦1. Such nitride semiconductor light emitting devices each include a light emitting structure obtained by sequentially growing an n-type nitride semiconductor layer, an active layer and a p-type nitride semiconductor layer. Light emission takes place as electrons from the n-type nitride semiconductor layer and holes from the p-type nitride semiconductor layer recombine in the active layer.
The light efficiency of nitride semiconductor light emitting devices is determined by external quantum efficiency and internal quantum efficiency. Here, the internal quantum efficiency reaches almost 100%, however the quantum external efficiency is excessively low.
Also, semiconductor light emitting devices are susceptible to electrostatic discharge (ESD), which is easily generated in people or objects. The resistance to ESD involves the reliability of semiconductor light emitting devices, and thus needs to be enhanced.